Why do subwoofers contain magnets?

Question

what are they used for?

Answer 1

If they didn't have magnets, they wouldn't work.

Answer 2

yes. all Electro-dynamic speakers have magnets.

see this :-)

http://www.picoodle.com/view.php?img=/4/...

The grey part is the magnet. it is a ring, or toroid (you see the profile of the spekaer magnetic assembly)

The black part is the core.

The voicecoil is blue, and the green part of the speaker is backplate. Brown arrows shows the magnetic field shape (don't look at direction).

The coil is situated between the core and magnet. When you push some current to the voicecoil, it creates electro-magnetic field, which reacts with the permanent (the ring) magnets by creating the force between the coil and the magnet. The coil is mounted on the suspended cone and spider (voice coil centering) so it moves the cone. The higher current you put in, the more force it makes. The stronger magnet and narrower space between the coil and magnet, the more force to the voice coil applied. So they must find the best compromise between magnet strenght, voice coil to magnet gap size and the voice coil mass to handle the power and not burn. it is a bit more difficult, but this is the base....

Answer 3

the magnet holds the speaker cone in a "neutral" position. when an outside source feeds the speaker an electrical current (ie sound). that electrical current causes the voice coil around the core of the speaker cone to repell away from the magnet on the back of the speaker. by the outside source sending a signal down the wires attached to the speaker in the proper manner. it will produce sound.

Answer 4

every speaker has a magnet, not just subs.  take about your ipod ear buds and they will have a little magnet.

Answer 5

wat they r used for is to pull the subwoofer cone back and forth to move air creating bass without them nothing would happen cuz there would be nothing for the electricity going threw them to pull on causing the sub to move